1. Field of the Invention
This invention relates generally to a torsional vibration isolator or compensator, more particularly to a torsional compensator for a motorcycle primary drive, and specifically to a compensator which transmits torque from a hub member to a sprocket member through an elastomeric member.
2. Description of the Prior Art
Torsional vibration isolators known in the art include cam type, helical spring, friction plate, spider type with elastomeric cushion in compression, and various other elastomeric spring arrangements. A motorcycle engine compensator on the primary drive of a motorcycle can reduce the noise, vibration and harness (NVH) that would otherwise be transmitted from the engine to the rear wheel. The benefit of the compensator manifests especially at low engine speeds when transmission gear rattle noise may be caused by excessive engine torsional vibration. Representative of the art of motorcycle engine compensators are U.S. Pat. Nos. 7,143,734, and 6,688,986 and U.S. Pat. Pub. No. 2009/0005181A1. Other devices for vibration isolation representative of the broader art include the crankshaft gear isolator of U.S. Pat. No. 5,931,052, the decoupling vibration isolator of U.S. Pat. Pub. No. 2007/0209899A1, the motor isolator of U.S. Pat. No. 5,884,893, and the sewing machine isolator of U.S. Pat. No. 2,765,759.